The Australian-born reliever has been excellent in his three years with the Athletics, putting up a 2.53 ERA in just under 200 innings and earning 64 saves. He was a pivotal part of an Oakland relief corps that finished sixth in the majors in bullpen ERA.
He could immediately supplant Johnson in the closer's role, and similar results might be safe for the Orioles to expect. Despite Johnson's league-leading 101 saves over the last two seasons, he and Balfour are very similar in terms of career ERA and WHIP. If the O's can land Balfour at less than the $10 million per season that Johnson was asking them for, this signing could be a big win for them.
Balfour could benefit significantly from playing in Baltimore as well. While Camden Yards is a much more hitter-friendly environment than the Oakland Coliseum, the Orioles heavy reliance on a ninth-inning curtain man could boost his market value in the future. On the other hand, he'll be 36 later this month, and he could be looking for three years due to the fact that this could be his last major-league deal.